Testing a Proportioning Valve?

trapster said
Mine are doing the same thing, and the rear locks up way too early. I suspect that whoever upgraded my 64 dart to duel master with disks in the front, did something wrong. I am considering adding a proportioning valve for the rears. Right now I don't have to step on the brakes very hard before one of the rears locks up. If I ride the brakes for a while it doesn't do it as bad. I have inspected the rear brakes and they are fine, no leakage or glazing. So I am following this

They probably just used the drum/drum distribution block instead of adding a proportioning valve. If you look at the pictures of the prop valves above and then look at where your lines split off down on the frame rail below the MC it’ll tell you. A distribution block is pretty small, just a splitter for the lines basically. If they left that and went disk/drum you’d get that problem.